/*
 * Copyright 2018 Google Inc.
 *
 * Use of this source code is governed by a BSD-style license that can be
 * found in the LICENSE file.
 */

#include "modules/sksg/include/SkSGGradient.h"

#include "include/core/SkColorSpace.h"
#include "include/core/SkPaint.h"
#include "include/effects/SkGradientShader.h"
#include "include/private/base/SkTPin.h"

namespace sksg {
sk_sp<SkShader> Gradient::onRevalidateShader()
{
    if (fColorStops.empty()) {
        return nullptr;
    }

    std::vector<SkColor4f> colors;
    std::vector<SkScalar> positions;
    colors.reserve(fColorStops.size());
    positions.reserve(fColorStops.size());

    SkScalar position = 0;
    for (const auto &stop : fColorStops) {
        colors.push_back(stop.fColor);
        position = SkTPin(stop.fPosition, position, 1.0f);
        positions.push_back(position);
    }

    // TODO: detect even stop distributions, pass null for positions.
    return this->onMakeShader(colors, positions);
}

sk_sp<SkShader> LinearGradient::onMakeShader(const std::vector<SkColor4f> &colors,
    const std::vector<SkScalar> &positions) const
{
    SkASSERT(colors.size() == positions.size());

    const SkPoint pts[] = { fStartPoint, fEndPoint };
    return SkGradientShader::MakeLinear(pts, colors.data(), nullptr, positions.data(), SkToInt(colors.size()),
        this->getTileMode());
}

sk_sp<SkShader> RadialGradient::onMakeShader(const std::vector<SkColor4f> &colors,
    const std::vector<SkScalar> &positions) const
{
    SkASSERT(colors.size() == positions.size());

    return (fStartRadius <= 0 && fStartCenter == fEndCenter) ?
        SkGradientShader::MakeRadial(fEndCenter, fEndRadius, colors.data(), nullptr, positions.data(),
        SkToInt(colors.size()), this->getTileMode()) :
        SkGradientShader::MakeTwoPointConical(fStartCenter, fStartRadius, fEndCenter, fEndRadius, colors.data(),
        nullptr, positions.data(), SkToInt(colors.size()), this->getTileMode());
}
} // namespace sksg
